Reserve Space for the MFT

by Mitch Tulloch [Published on 9 Jan. 2008 / Last Updated on 9 Jan. 2008]

Boost NTFS performance by reserving space for the MFT

,NTFS on Windows XP improves performance of the Master File Table (MFT) over Windows 2000 by not placing some of the MFT metadata files at the start of the disk. This enhancement alone can boost NTFS performance on Windows XP by up to 10 percent over Windows 2000. But you can squeeze out even better performance by ensuring that your drive has enough room for the MTF to grow if it has to. This will prevent the MTF from becoming fragmented, which is important because the Disk Defragmenter tool can't defragment the MFT.

By default, Windows XP reserves 12.5 percent of each NTFS volume (an area called the MFT zone) for exclusive use of the MFT. So if you plan to store tons of small files (under 8K, say) on your volume, your MFT may run out of space before your volume's free space does, and the result will be MFT fragmentation. To prevent this from happening, you can reserve additional space for the MFT using the fsutil command:

fsutil behavior set mftzone 2

This doubles the size of the reserved MFT zone to 25 percent of the volume. Of course, this means you lose 12.5 percent of the free space used to store files themselves, so there's a trade-off to consider when implementing this change. You can even make more aggressive changes using set mftzone 3, which reserves 37.5 percent of the volume for the MFT, or set mftzone 4, which reserves a whopping 50 percent. These extreme settings are only useful, however, if you have zillions of files, each smaller than about 1K.

To reset the MFT zone size according to your needs, do the following:

Run the fsutil command as described previously.
Reboot your system.
Create the volumes you need.

To return to the default behavior of reserving 12.5 percent of each volume for MFT, use the fsutil behavior set mftzone 1.

See Also

The Author — Mitch Tulloch

Mitch Tulloch is a well-known expert on Windows Server administration and cloud computing technologies. He has published over a thousand articles on information technology topics and has written, contributed to or been series editor for over 50 books.

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